5. Description of the parameters in PION parameter files

divide up parameters by topic and describe them in tables.

5.1. Stellar Winds

Stellar winds in PION are implemented in 3 modules: a constant wind, an evolving wind, and a latitude-dependent wind. The parameter file for a constant wind has a number of parameters that should be set, quoted below with the expected units. They are stored in these units in the SWP struct of type stellarwind_params.

Parameter	Description	Units/values
WIND_[i]_pos[n]	Star position \(n\in[0,1,2]\)	cm
WIND_[i]_radius	Radius of wind injection region	cm
WIND_[i]_type	[Constant, evolving, latitude dependent]	[0,1,2]
WIND_[i]_mdot	Mass-loss rate from star (dot{M})	\(\mathrm{M_{\odot}\,yr}^{-1}\)
WIND_[i]_vinf	Terminal velocity of wind	\(\mathrm{km\,s}^{-1}\)
WIND_[i]_vrot	Equatorial rotation velocity	\(\mathrm{km\,s}^{-1}\)
WIND_[i]_temp	Effective Temperature of star, \(T_\mathrm{eff}\)	K
WIND_[i]_Rstr	Radius of star	cm
WIND_[i]_Bstr	Strength of surface magnetic field	Gauss
WIND_[i]_TR[n]	Value of tracer \(n\) in wind	Usually \(\in [0,1]\)
WIND_[i]_evofile	Text file with data for evolving wind	Default is NOFILE
WIND_[i]_t_offset	offset of sim time from evolution time	Default is 0.0
WIND_[i]_t_scalefac	scaling simulation time to evolution time	Default is 1.0
WIND_[i]_updatefreq	How often to update the wind	seconds
WIND_[i]_enhance_mdot	ad-hoc flag to increase \(\dot{M}\)	Default is 0

For constant winds, these data are stored in the global struct SWP, defined in pion/source/constants.h, using these units. In simulation snapshots they also have the same units. The evolving wind file should have all units in CGS.